I am placing a 40 pin GPIO header (from the LibrePCB library) in my schematic. Pin 1 is top left, as specified in the component.
When adding it to the board it’s added to the top layer by default. Following a recommendation in here I pressed “F” to flip it to the lower side of the board, which works great. However, the Pin 1 is now on the top right, which for this type of connector would be incorrect.
I am pretty sure I can just trace the connections from the pins to the other components, however, they no longer correspond to the schematics and the DRC is very unhappy…
What would be the correct procedure to do that? I could imagine to add a new device to the library, with the pins flipped, however, maybe there is a simpler approach.
Pin 1 stays pin 1, even if you mirror the device in the board. Open the 3D viewer and you should understand it’s always the top left pin. If you mirror the package, pin 1 appears at top right in the 2D viewer because you’re looking through the board. But in the 3D viewer you can look at the board from bottom (as it would be in real life) and pin 1 is at the top left.
No need to mirror anything in the schematic or to trace differently.
Thank you for your reply @ubruhin. I fully agree with you, however, in this case the pin header is kinda like a pass through device. From the top view of the PCB pin 1 needs to stay at top left, as this is the mounting direction of the board (pushed onto the GPIO header of a Raspberry PI), so pin 1 would need to be top left when viewed from the top.
I will upload a screen shot to illustrate the layout.
By using the “mirror” option in the schematics I solved my issue, as now I can wire up the correct pins.
Schematics with the option “mirrored” selected for the 40 pin header:
Ah yeah for pass-through device the situation is not so clear as the pin-1 definition depends on from which side you look at it If it’s the wrong way around, swapping the pins in the schematic is the solution (whether mirror the symbol or not doesn’t matter for the circuit, it’s just esthetics)
If it’s the wrong way around, swapping the pins in the schematic is the solution 
(whether mirror the symbol or not doesn’t matter for the circuit, it’s just esthetics)
Thanks